COUNT RUMFORD (by permission of the Royal Institution, London) Cover Illustration by kind permission of Harvard University. Bequest of Edmund Cogswell Converse. MEN OF PHYSICS BENJAMIN THOMPSON- COUNT RUMFORD Count Rumford on the Nature of Heat SANBORN C. BROWN Massachusetts Institute of Technology PERGAMON PRESS OXFORD · LONDON · EDINBURGH · NEW YORK TORONTO · SYDNEY · PARIS · BRAUNSCHWEIG PERGAMON PRESS LTD., Headington Hill Hall, Oxford 4 & 5 Fitzroy Square, London W. 1 PERGAMON PRESS (SCOTLAND) LTD., 2 & 3 Teviot Place, Edinburgh 1 PERGAMON PRESS INC., 44-01 21st Street, Long Island City, New York 11101 PERGAMON OF CANADA LTD., 6 Adelaide Street East, Toronto, Ontario PERGAMON PRESS (AUST.) PTY. LTD., 20-22 Margaret Street, Sydney, New South Wales PERGAMON PRESS S.A.R.L., 24 rue des Écoles, Paris 5 e VIEWEG & SOHN GmbH, Burgplatz 1, Braunschweig Copyright © 1967 Pergamon Press Ltd. First edition 1967 Library of Congress Catalog Card No. 66-28414 Printed in Great Britain by A. Wheaton & Co. Ltd., Exeter This book is sold subject to the condition that it shall not, by way of trade, be lent, resold, hired out, or otherwise disposed of without the publisher's consent, in any form of binding or cover other than that in which it is published. (3108/67) PREFACE THE publication explosion in scientific literature had dictated such an economy of publication space that the periodical literature in physics at the present time is written in a peculiar type of clipped language and laconic style which conveys nothing but the bare outline of the scientific contribution. Any attempt to produce an interesting story or to speculate on the value or implications of the contribution would be ruthlessly edited from a manuscript if it were to be accepted for publication in any of the scientific journals at the present time. This has not always been the case and in the eighteenth and early nineteenth centuries the accepted scientific writings were often attempts at literary efforts which were aimed at being as interesting to the general public as it was useful to the professional natural philosopher. At the present time, the only professionally accepted equivalent to eighteenth-century scientific reporting is the colloquium talk or the occasional hour-long invited paper to professional society. In this process of streamlining and making efficient scientific reporting, something of very real value has been lost which shows up in many ways, including the currently popular image of the scientific endeavor as one of inhuman attention to "cold fact" and the reputation of the scientific enterprise as one in which the scientist himself, as a human being, must never appear. The fact is, of course, that the scientist today is just as human as the scientist of 150 to 200 years ago but until we find some better way of transmitting scientific information than the present written scientific communication to cope with the information explosion of the modern scientific age, the current tendency will continue toward making the scientific paper less and less readable to more and more people. vi i Vlli PREFACE It is very difficult for the nonscientist of the present day to develop an adequate picture of the scientific enterprise. As we have just mentioned, the scientific literature of today uses a kind of professional shorthand which has communication significance only to the trained professional. Furthermore, the prerequisite background education necessary to understand and evaluate scien­ tific advancements which are of current interest to the research world in physics is of such a detailed and specific nature as to make modern examples of scientific methodology difficult, if not im­ possible, to capitalize upon. On the other hand, good scientific work is by no means limited to the modern idiom and the better examples of the operation of scientists in trying to understand the laws of nature can more often be found in the historical perspec­ tive than in today's laboratories and literature. With this in mind, the current volume has been assembled. Count Rumford typifies much of the scientific enterprise of the eighteenth century. Few of the leading research scientists were trained professionals. The teaching profession was a rigidly dis­ ciplined and, in general, poorly paid profession which allowed the teachers neither the time nor the energy for independent investiga­ tion. The necessary background to arrive at the leading edge of science could be assimilated by anyone who had the time and inclination to study the then rather meager literature on the subject of physics so that the whole social structure of the scientific enterprise encouraged progress in natural philosophy being made by those not primarily engaged in educating the youth. It was an age in which the learned society fulfilled the function of our present-day research laboratory and the scientific communication was written to be interesting to the general educated world. Freed from any restriction on length or the efficiency of information transmission, the eighteenth-century physicist could describe not only his scientific contribution but the manner in which he was led to the subject matter under discussion. Thus, a much clearer picture emerged of the actual progress of scientific research than is now to be gained by reading the professional literature domi­ nated as it is by the requirement for efficiency and sterile pedantry. PREFACE IX You should not only read these scientific discourses as interest­ ing reports of scientific development but hopefully the character of the scientific enterprise and the scientists involved will be more realistically portrayed. If you are interested in the extraordinary life of Count Rumford himself, a short biography entitled "Count Rumford" by Sanborn C. Brown was published by Doubleday and Co. Inc., Garden City, New York, in 1962 and by Heinemann Educational Books, Ltd. of London in 1964. A BIOGRAPHICAL SKETCH OF COUNT RUMFORD, BENJAMIN THOMPSON (1753-1814) THE details of a man's life can really never be separated from his contributions to society be they the work of his hands or the work of his brain. However, it is not practical in a volume of this sort to combine a reprinting of Rumford's scientific works with the details of his life which obviously interacted with his scientific endeavors. Nevertheless it seems worthwhile to sketch out the kind of life he led and the type of personality the author of these scien­ tific papers exhibited to the world around him. Count Rumford was born with the name Benjamin Thompson on March 23, 1753, in Woburn, Massachusetts, a small village close to Boston. There was nothing particularly noteworthy about his childhood, but he came to the attention of the public in his early twenties by actively working for the British Crown at a time when those who were actually rebelling against the British rule were successfully making it not only unhealthy but physically dangerous for Loyalists to stay in the New England area. There were, of course, many people in the American Colonies that were loyal to George III, but the details of their lives were usually obscured by the simple fact that they fled to either Nova Scotia or England and their property was confiscated by the victorious Americans, or they were farmers, shopkeepers and artisans, the records of whose lives often go unrecorded. This is not the case, however, with Benjamin Thompson through a series of rather remarkable events. Throughout his life Benjamin Thompson demonstrated a con­ sistent ability to capitalize upon available circumstances to further 3 4 BENJAMIN THOMPSON, COUNT RUMFORD his own ends. He first catapulted himself into the public eye when at the age of 19 he married a wealthy widow, fourteen years his senior, and thereby became one of the wealthiest landholders in what is now the State of New Hampshire. Sarah Rolfe had married a man much older than herself who was a colonel in the Royal Governor's Militia and an honored member of Governor Went- worth's entourage. It was, therefore, not surprising that when young Benjamin Thompson took Colonel Rolfe's widow as a wife he should find easy access to the fashionable society which gravi­ tated about the Royal Governor's establishments. As a mark of Governor Wentworth's approbation of the marriage, not only did the Governor sign the marriage contract himself, but made the young lad a major in the Colonial Militia. Major Thompson, for his part, returned excellent service to the Loyalist cause by organizing a technique for rounding up deserters from the Regular British Army with such efficiency that his zeal was commended in dispatches from the Colonies to the Earl of Dartmouth in London. As the course of revolution built up toward its inevitable climax of open hostility, Thompson's position as an active Loyalist in­ creased his physical danger to an extent that in the winter of 1774, after having been openly accused of activities inimical to the cause of "American liberty", he fled from Concord, New Hamp­ shire, and returned to Woburn, Massachusetts, and his family home, leaving his wife and an infant daughter to pacify an angry citizenry. While Major Thompson was in Woburn ostensibly to get his affairs in order so that he could become an officer in George Washington's army, actually he continued his service to the Crown as a spy on the American establishment. Here he demonstrated two traits which were characteristic of his entire life. One of these was the fact that he was a very careful observer and recorded what he saw with great precision and attention to detail. This charac­ teristic is amply borne out in his scientific papers and will be evident to all who read this volume. Using his Woburn home as a base, Benjamin Thompson wrote a most careful and detailed docu- A BIOGRAPHICAL SKETCH 5 ment for the British Military Establishment entitled "Observations on the Present State of the Rebel Army", which not only chronicled the physical and military details of the forces under Washington's command in Cambridge, but discussed problems of morale and tactics in a most perceptive and useful (to the British) way. The other facet which stands out so clearly in his activities at this time in Woburn was the very practical application of his scientific learning. Thompson was the author of the first known intelligence written in secret ink in the American Revolution, and his technical excellence in this area was not exceeded until the First World War. It was obvious that he had so much faith in its superiority that he was willing to risk his life on the security of his secret ink letters, and his whole approach to this use of the then most modern technology was a tribute to his ability as an experi­ mental scientist. Although Thompson's science and technology was excellent enough so that his espionage activities were never discovered by his contemporaries, his behavior in the eyes of the citizens of Woburn and Cambridge was not above suspicion, and after being examined twice by local "Committees of Safety", Benjamin Thompson decided that he could no longer trust his luck in the American camp and he fled to the safety of the British Army in Boston in October 1775. When the military position of the British Army in Boston became untenable, the major part of the forces embarked for the safety of the Loyalist city of Halifax, Nova Scotia, but Thompson, as one of the most knowledgeable observers of the American situation, was attached to that small group of experts who went directly to London to report on the military situation to Lord George Germain, whose responsibility it was to crush the rebel­ lious Colonies for George III. London was in desperate need of reliable information about what was going on in the Massachusetts Bay Colony, and when the aggressively intelligent and well-informed Thompson appeared on the scene, he was such a welcome addition to the government bureaucracy that he rose rapidly in the favor of the King's ministers. 6 BENJAMIN THOMPSON, COUNT RUMFORD Benjamin Thompson landed in London during the summer of 1776 and almost immediately took up a position as private secre­ tary to Lord George Germain, Secretary of State for the Colonies. Within three years Thompson had made himself so useful to the British Government that he received the position of Secretary of the Province of Georgia, and in 1780 he was made Under Secretary of State for the Northern Department. As he rose in government circles, he found time not only to be a useful political figure, but also to gain a reputation as a serious natural philosopher which earned him, in 1781, Fellowship in the Royal Society. The research work which won him this honor was a series of studies of the force of fired gunpowder which he carried out in the summer of 1778 on the summer estate of Lord George Germain. Thompson per­ fected a method of testing the force of gunpowder by means of a ballistic pendulum which is still a common physics demonstration in using the conservation of momentum for measuring the velocity of rifle bullets. Thompson was professionally considered a military man and his ballistics studies greatly increased his reputation. However, it was not just the engineering aspect of gunnery that interested him. Even at the age of 25, he was searching for a clue as to the nature of heat, and many of his speculations on the nature of the force behind an explosion of gunpowder centered around a search for the explanation of the nature of heat itself. The summer following his experimental studies at Lord George Germain's Stoneland Lodge he went on a three-months' tour of duty with Admiral Hardy's fleet in the English Channel, and here not only did he send back to Lord George detailed accounts of the inefficiency of the operation of the British fleet, but he carried out an extensive continuation of his ballistics studies with the great guns of the fleet at his disposal. So well was he doing in his rise to fame and fortune that it is amazing to discover that in 1781 he suddenly left his position in London and sailed to take up an active command of the King's American Dragoons in the area of New York. Local gossip at the time linked his name with a notorious French spy who had been